Many modern day household refrigerators are divided into two compartments, typically with a freezer compartment on the top and a fresh food compartment on the bottom. A partition within the refrigerator separates the cabinet into these two compartments, each of which has its own door. It is desirable to incorporate a mullion across the cabinet in front of the partition and secured to the cabinet outer case or housing to provide a pleasing appearance. The separate access doors for the freezer and fresh food compartments normally are hingedly attached to the cabinet outer case. It is important for the proper fit of the doors that the width and rectangularity of the cabinet be properly maintained under normal or designed loads. Typically modern household refrigerators employ a sheet metal outer housing and an inner liner of metal or plastic with foam insulation, such as polyurethane, interposed therebetween. The foam material is introduced into the space between the housing and liner in a liquid/gas form and is then allowed to expand throughout the space and solidify by curing. As the foam expands it exerts a force which tends to cause the cabinet to bow. It is desirable to reinforce the cabinet, particularly at the front where the doors are to be hung, in order to assure that the door openings remain square during the foaming operation.
Once solid the foam inherently adheres to both the outer case and the inner liner and thus add rigidity to the cabinet structure. This has enabled manufacturers to reduce the thickness of the outer cabinet; however, in some instances the cabinet may tend to deflect due to uneven floors or the force placed on the cabinet by the weight of the doors. Such detection can cause a misalignment of one or both of the doors. Thus it is important to insure that the cabinet, particularly the front portion, remains square.
It has become a practice to incorporate a number of electrically operated devices in the doors of refrigerators for operation or viewing from the exterior of the refrigerator without opening the door. For example it is quite common to have through the door ice dispensers, ice crushers and water dispensers. Additionally it is becoming more common to have indicator panels and lights mounted on the door to be visible from the outside and inform users of various conditions of the refrigerator and possible malfunctions. All of these devices need electric power. In addition the same basic cabinet may be used for several different models which have many different combinations of door-mounted, electrically powered accessories. It is desirable to be able to install the wiring late in the manufacturing process, particularly after the foam insulation has been formed. This enables model differentiation to accomplished late in the manufacturing process and thus simplifies manufacturing.
The interior of a refrigerator is maintained at a temperature substantially lower than the exterior of the cabinet and heat transfer tends to cause the exterior of the cabinet around the doors to be sufficiently cool that moisture condenses on the metal wall. The cabinet appears to be "sweating". Mullion heaters often are placed within the cabinet just outside the edge of the doors, particularly the door to the freezer compartment, to prevent sweating. Such heaters normally are electrical resistance elements mounted within the outer housing and held in place by the foam insulation. Obviously with such a construction the heating element cannot be replaced. One approach to provide greater assurance of having an operative heater element is to embed two or more elements and have a changeable connection so that, if one becomes inoperative, the electrical connection can be changed to another to continue to provide the heating. This is inefficient from a cost standpoint as the multiple heaters are included in each refrigerator while, in many cases, only one element is ever used. Thus it is desirable to have a cabinet construction wherein the mullion heaters are easily replaced.
Accordingly, by the present invention means are provided to insure that the front of the refrigerator housing particularly the housing door openings remain square during production and operation of the refrigerator and that the cabinet has sufficient strength to support the doors.
Additionally a cabinet structure is provided which enables electrical wiring easily to be installed late in the manufacturing process for facilitating the use of various door mounted electrically operated accessories.
Additionally a refrigerator cabinet is provided including means for easy installation and replacement of mullion heaters.